a. Field of the Invention
This inventin relates to a casing stabbing apparatus for running casing pipe into a well bore.
B. Description of the Prior Art
During the running of casing pipe into a well bore, it has heretofore been customary practice to raise an add-on section of casing pipe into the derrick by the use of wireline slings or the like. Thereafter, the add-on section is moved to the proper vertical alignment for stabbing of the lower pin end of the casing pipe into the upper box end of the casing pipe string being supported in the well bore by appropriate slips or the like. Once the add-on section of casing pipe is properly axially aligned, then conventional power tongs are utilized to rotate the same, thereby threading the add-on section into the upper end of the casing being supported in the aforesaid slips. However, the stabbing operation for adding on a section of casing pipe is much more critical than with other types of pipe, as for example, conventional drill pipe. This arises out of the fact that casing pipe have a different type thread configuration, with the result that axial alignment is more important in performing the casing stabbing operation.
Heretofore, the add-on section of the casing pipe has been manipulated by an observer positioned on the derrick floor. However, an operator so located is not in the best position for observing the proper axial alignment and performing other required manipulative steps. As a result, there have been developed what are called casing stabbing platforms, which are suspended on wirelines held within the derrick, such that an operator supported thereon can be raised above the derrick floor to obtain a better view of the stabbing operation and thereby direct such operations from such vantage point. In certain instances, apparatus of the aforesaid type permit the operator to manually apply the proper lateral forces to the add-on section to perfect the axial alignment while the add-on section is actually being supported by a conventional elevator or sling. However, these type of prior art devices are not fully satisfactory for the reason that such platforms are not very stable; the operator is not situated proximate to not very stable; the operator is not situated proximate to the add-on section at all times; and such operator cannot control the axial stabbing operation in most instances. Moreover, in those instances where the operator must physically apply lateral forces to the add-on section, great manual effort is required in certain instances, which is not very satisfactory.